The present invention relates to an improved method and apparatus for simultaneously tracing a plurality of transmission lines from a first location to a second location. Specifically, the present invention is useful for tracing a plurality of twisted pair telephone transmission lines contained within a telecommunications cable.
Modern copper telecommunications cables typically contain as many as 600 twisted wire pairs ("line pairs") and may extend several miles in length. Often it becomes necessary to monitor the performance of a given line pair or a number of line pairs within a telecommunications cable. For example, a technician may be required to trace a number of lines from one location to the next. Thus, in order to reduce the cost and the time required to trace the line pairs, it is highly desirable to be able to trace several line pairs simultaneously.
Prior art methods for tracing line pairs within telecommunications cables are, unable to simultaneously trace multiple line pairs. Each line pair must be traced individually. This is not only inefficient and expensive, but is also tedious when the ends of the telecommunications cable under test are separated by several miles.
Prior art apparatuses for tracing line pairs within telecommunications cables employ signal generators which apply square wave signals to a single line pair. These square wave signals are typically 5-10 volts in amplitude and have a frequency within the range of 400-1500 Hz. The signals may be continuous or may be switched between two frequencies to add a "warble" sound which is easier for an operator or technician to hear or detect.
In prior art methods, a signal generator is connected to one end of the telecommunications cable. Specifically, the signal generator is connected to the line pair to being traced. A high input impedance amplifier is then held in close proximity to the line pairs at the opposite end of the cable. When the amplifier is close to the actual line pair containing the square wave signal, the signal is capacitively coupled to the amplifier and becomes audible. If another line is to be traced, the signal generator must be disconnected from its current line pair and connected to the next line pair to be traced. Having to switch the square wave generator for each line pair to be traced (each "traced line pair"), is very time consuming particularly when the traced line pairs are part of a telecommunications cable several miles in length. Thus, there is a need in the art for a method and apparatus that will provide simultaneous tracing of several line pairs.
Accordingly, it is an object of the present invention to provide an improved method for tracing a plurality of transmission lines from a first location to a second location.
It is a further object of the invention to provide an apparatus for tracing a plurality of transmission lines from a first location to a second location.
Yet another object of the invention is to provide a method and apparatus for simultaneously tracing a plurality of transmission lines from a first location to a second location.
A further object of the invention is to provide a method and apparatus which allows one traced line to be easily distinguished from any other traced line.
Another object of the invention is to provide a method and apparatus that allows the human ear to be used to easily distinguish one traced line from any other traced line.
It is a still further object of the invention to provide a compact and cost effective apparatus that employs a single signal generator for use in simultaneously tracing a plurality of transmission lines.